Use updated version of opm-common as submodule

* Adjustments to build system for opm-common
* Add opm-common as submodule
* Disable use of unity build for opm-common

ApplicationLibCode/UnitTests/HDF5FileWriter-Test.cpp

@@ -13,6 +13,11 @@
 #include <iostream>
 
 #include "RifHdf5SummaryExporter.h"
+
+#ifdef _MSC_VER
+// Disable warning from external library to make sure treat warnings as error works
+#pragma warning( disable : 4267 )
+#endif
 #include "opm/io/eclipse/ESmry.hpp"
 #include <numeric>